1. Field of the Invention
This invention relates to systems for refueling aircraft while in flight and especially to reel systems for use in an aircraft refueling apparatus.
2. Discussion of Related Art
In many instances, it is desirable to reduce the time of flight of an aircraft by refueling the craft while in flight and thus avoiding the necessity of landing, refueling and taking off again. In order to facilitate such in-flight refueling, systems have been developed which can be attached to a tanker plane for coupling to an aircraft to be refueled.
A conventional system for providing aircraft-to-aircraft coupling is in the form of a module or pod which can be connected to the bottom of the plane to be used as a tanker. The pod contains a tank filled with aircraft fuel to be transferred to the other aircraft. Also, the pod contains a hose with an attachment mechanism for engagement with the aircraft fuel tank of the other plane. A reel is also contained in the pod for unwinding the hose prior to refueling and rewinding the hose into the pod after the refueling operation has been completed. In such a conventional design, the hose wraps circumferentially about the reel and extends tangentially from the reel in a direction transverse to the reel axis. In order to accommodate a sufficient length of hose to reach an aircraft to be refueled, the hose on such a transverse reel must be wrapped in layers, and several layers of hose must be provided. In order to ensure that the lower layers of a hose wrapped on such a transverse reel are not crushed by the outer layers, the hose wrapping must include convolutions. This leads to a relatively complicated reel design which is expensive to manufacture, difficult to perform stress analysis on, and expensive to produce. Additionally, a transverse reel has the disadvantage that the pod in which the reel is mounted must be made relatively wide to include the entire reel within it. This leads to a relatively larger than desirable pod structure and can also increase the overall weight of the structure.
Alternately, the reel can be incorporated inside a plane designed as a tanker for refueling purposes.